Casing for a fluid flow machine

ABSTRACT

A casing of a fluid flow machine is provided. The casing includes two half-casings which abut against each other on an axial parting plane. The casing also includes a fastening device for fastening the two half-casings to each other and for pretensioning the two half-casings against each other. The fastening device includes at least one coil which wraps around the half-casings. The coil is made up of at least one tension cable having at least one wire.

FIELD OF INVENTION

The present invention refers to a casing for a fluid flow machine, especially for a turbomachine. The invention also refers to an installation device for attaching a coil on such a casing.

BACKGROUND

Fluid flow machines, especially turbomachines such as steam turbines, gas turbines, compressors, hydroturbines or hydropumps, are exposed to very high pressure loads during operation. In the case of steam turbines, gas turbines and compressors or chargers, additional loads are added as a result of high temperatures. These loads have to be able to be absorbed by corresponding casings or casings of the fluid flow machines. Such casings as a rule are assembled from two half-shells which abut against each other in the region of an axial parting plane of the casing. The axial orientation of the casing is determined in this case by the orientation of a rotor of such a fluid flow machine, the rotational axis of which defines the axial direction. The two casing half-shells or half-casings have to be fastened to each other with a comparatively large force in order to be able to meet the demands which exist during operation. A type of construction with a single casing and a type of construction with a double casing, which comprises an inner casing and an outer casing, are known.

For fastening the two half-casings to each other different techniques are known. For example, shrink rings can be attached on the casing on the outside. In this case, it is disadvantageous that the casing must have a relatively large wall thickness. Furthermore, the shrink rings have a relatively large dimension in the radial direction, as a result of which the casing is altogether relatively large in construction. Creep deformations, which occur in the course of operation of the fluid flow machine, in this case are comparatively large since the temperature gradient is correspondingly large across the relatively large wall thickness. This especially applies to an inner casing since this is exposed to intense heat from the inside and at the same time is cooled from the outside. When running up and shutting down the fluid flow machine, correspondingly larger deformations can occur on account of the large dimensions in the radial direction. When removing the shrink rings, for example for maintenance purposes, comparatively large, permanent deformations of the casing can appear. As a result of this, a cost-intensive reworking of the contact surfaces in the region of the parting plane can also become necessary. The shrinking-on during assembly and the de-shrinking during dismantling of the casing is a time-consuming process. In addition, the production costs are comparatively high.

Alternatively, it is known to equip the half-casings with connecting flanges in the parting planes. Such flanges must be constructed comparatively thick in order to be able to transfer the necessary forces. As a result of this, the casing has a comparatively heavy weight which at the same time increases the production costs. For the threaded connecting of the flanges, bolts are used which must be able to bear high loads and are correspondingly expensive. Furthermore, it is necessary to regularly retighten or to check the bolted connections.

As long as an inner casing is equipped with such fastening flanges, the outer casing must also be dimensioned correspondingly larger. An uneven pressure distribution can develop along the parting plane since the bolted connections enable only singular force transmission. As a result of this, the loads of the casing are limited by temperature and pressure. In the region of such fastening flanges a very large material thickness prevails, as a result of which the temperature gradient can trigger comparatively large plastic deformations. The fixing of the half-casings along the fastening flanges can bring about deformation of the casing in the case of high pressures and/or in the case of high thermal loads. Therefore, the per se circular interior of the casing becomes slightly elliptical as a result of these loads. In the case of fluid flow machines which have a rotor with rotor blades, problems consequently arise in the radial clearance between the rotor blade tips and corresponding casing-side mating surfaces. The gaps must be selected correspondingly large in order to avoid contact during operation. Large gaps, however, can lead to comparatively large losses and to reduced efficiency of the respective fluid flow machine. Also in this case, after a dismantling of the casing it may be necessary to expensively rework the fastening flanges and/or the half-casings in the region of the parting plane in order to eliminate permanent deformations which have developed during operation.

In the case of single casings, in addition to the aforementioned disadvantages which occur when using shrink rings or when using fastening flanges, there is the risk of steam or hot gas being able to escape into the environment if a plastic deformation of the half-casings in the region of the parting plane allows a leak to develop.

SUMMARY

The invention should provide a remedy for this. The invention, as is characterized in the claims, deals with the problem of disclosing an improved embodiment for a casing of the type referred to in the introduction, which is especially characterized by reduced deformation of the casing during operation and/or by reduced weight and/or by reduced production and maintenance costs.

According to the invention, this problem is solved by the subjects of the independent claims. Advantageous embodiments are the subject of the dependent claims.

The invention is based on the general idea of fastening the two half-casings to each other by means of a coil which wraps around the half-casings on the outside and which is formed with at least one tensionally-loaded cable which comprises at least one wire. Multifarious advantages ensue as a result of the type of construction which is proposed according to the invention. On the one hand, the coil can be almost optimally adapted to the rotational symmetry of the casing, which enables an optimum force distribution along the casing. On the other hand, the casing can be designed comparatively thin on account of the homogeneous force distribution, as a result of which the weight of the casing and the production costs can also be reduced. A thin wall thickness of the casing reduces the temperature sensitivity and especially reduces creep deformations due to temperature gradients. In addition, the coil as such requires comparatively little installation space in the radial direction, as a result of which the space requirement can be reduced in addition to the reduced wall thickness. The tension cable, which can be loaded under tension and can especially be formed by means of a wire cable formed from a plurality of wires, has a significantly higher stability and creep strength in its tensioning direction than the cast material of the half-casings. This also applies when the tension cable and the half-casings are produced from the same material. This is attributable to the different sizes. By the same token, this is attributable to the cold processing of the tension cable which contributes to an advantageous internal material structure, especially with regard to fiber orientation. Furthermore, when using such a coil, fastening flanges can be dispensed with as can highly-loadable pretensioning bolts. Providing the coil is used in an inner casing, the outer casing can also be designed correspondingly smaller. The comparatively homogeneous force distribution along the sealing face in the parting plane, in which the two half-casings abut against each other, enables a higher pressure loading and/or temperature loading of the casing even during transient operating conditions, which reduces the susceptibility of the casing to plastic deformations of the sealing face. As a rule, cost-intensive reworking of the contact zones of the half-casings which lie in the parting plane can also be dispensed with since the deformations which customarily occur during operation turn out to be considerably smaller. For producing the coils in the case of different casings, the use and the provision of tension cables with a few standard cable diameters suffice. Expensive special fabrications of bolted flange connections can be dispensed with. Furthermore, the tension cable can be simply stored and quickly made available. By using such coils for fastening the half-casings to each other time-consuming installation and dismantling processes, as are necessary for example when attaching and removing shrink rings, are also dispensed with. The reliability of a fastening which is created by means of the coil is increased which simplifies the operation of the fluid flow machine which is equipped therewith. An important advantage of the fastening according to the invention can also be seen in the fact that the retaining forces are introduced into the casing not only in the axial direction but also radially and in so doing are distributed essentially homogeneously in the circumferential direction, as a result of which a deformation of the cross section on account of high pressures and temperatures is reduced. An elliptical deformation of the per se circular cross section can be significantly reduced or even avoided. As a result of this, it is especially possible to reduce a radial gap between rotor blades of a rotor of the fluid flow machine and stator-side or casing-side mating surfaces with regard to the gap width. For example, the gap widths can be reduced in labyrinth seals. As a result of this, the efficiency of the fluid flow machine which is equipped in this way can especially be improved. Furthermore, there is now the possibility of using brush seals even in the case of high-pressure turbines and medium-pressure turbines, which was not previously possible due to the elliptical casing deformation, which also leads to an efficiency increase of the turbine which is equipped with them. Another important aspect is seen in the fact that the tension cable is exposed to altogether considerably lower temperatures than for example the tensioning bolts of a fastening flange, because such tensioning bolts extend inside the respective fastening flange and are consequently arranged comparatively close to the inner surface of the respective casing which especially delimits a hot gas path of a gas turbine or a hot high-pressure region of a steam turbine. In contrast to this, the tension cable is located on the outer side of the respective casing and can also be directly exposed to cooling. On account of the considerably lower temperatures in the tension cable and the high material strength associated with this, under the same operating conditions this can ensure a considerably better clamping of the two half-casings to each other than a corresponding flange connection with tensioning bolts. Overall, the production costs of such a casing can also be reduced. In addition, the improved reliability of the proposed fastening enables an increase of the maintenance intervals, as a result of which downtimes of the turbomachine which is equipped with the casing are reduced during its life.

The problem upon which the invention is based is also solved by means of an installation device for attaching a coil on a casing according to the invention. Such an installation device is characterized in that provision is made for an abutment device which can be attached, or is attached, in a fixed manner on the casing and upon which at least one tensioning device can be supported, which serves for introducing a tensioning force into the tension cable. The forces which are required for the tensioning can therefore be borne directly on the casing which reduces the equipment cost for producing the desired pretensioned coil.

Further important features and advantages of the present invention result from the dependent claims, from the drawings and from the associated figure description with reference to the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred exemplary embodiments of the invention are shown in the drawings and are explained in more detail in the following description, wherein like designations refer to the same, or similar, or functionally the same components.

In the drawing, schematically in each case,

FIG. 1 shows a partially sectioned side view of a casing,

FIG. 2 shows a half cross section of the casing from FIG. 1 corresponding to lines of intersection A,

FIG. 3 shows a half cross section of the casing from FIG. 1 corresponding to lines of intersection B,

FIG. 4 shows a non-sectioned side view of a casing with casing diameters which increase in one direction,

FIG. 5 shows a non-sectioned side view of a casing with casing diameters which vary in the axial direction,

FIG. 6 shows a non-sectioned plan view of a casing with a combination of conventional bolted connection (on the left) and cable coil (on the right),

FIG. 7 shows a non-sectioned side view of a casing with a combination of conventional shrink ring connection (on the left) and cable coil (on the right),

FIG. 8 shows a half axial section of the casing with installation device attached thereupon,

FIG. 9 shows a plan view of the casing in the region of the installation device according to FIG. 8,

FIG. 10 shows a view as in FIG. 8, but in the case of another embodiment of the installation device,

FIG. 11 shows an axial view of the casing with an installation device, wherein the casing is rotated in the cable coil,

FIG. 12 shows an installation device as in FIG. 11, but additionally with springs on the axial slide.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Corresponding to FIG. 1, a casing 1 of a fluid flow machine, which is not otherwise shown, comprises two half-casings 2, 3, specifically especially an upper half-casing 2 and a lower half-casing 3. The two half-casings 2, 3 abut against each other in an axial parting plane 4, as a result of which the casing 1 is closed in the circumferential direction. In addition, the casing 1 comprises a fastening device 5 which is designed so that with this the two half-casings 2, 3 can be fastened to each other and can be pretensioned against each other.

The said fastening device 5 has at least one coil 6 which is formed by at least one tension cable 7. The coil 6 wraps around the two half-casings 2, 3 on their outer side. The wrapping is carried out in this case in the circumferential direction, or helically. The helically configured coil 6 in this case expediently has a pitch 8 which corresponds to a cable thickness or to a cable diameter 9. Other pitches 8 are also conceivable. The tension cable 7 can be formed by a single wire so that it can also be referred to as a tension wire 7. An embodiment in which the tension cable comprises a plurality of wires which together form a wire cable is also possible. As wire, a steel wire is preferably used. At very high temperatures, for example in the case of steam turbines with steam inlet temperatures above 700 degrees C., as are currently designed, a nickel-based material wire can also be used instead of a steel wire.

In the case of the fluid flow machine, the casing 1 of which is equipped with such a coil 6, it is preferably a turbomachine such as a steam turbine, a gas turbine, a compressor or charger, a hydroturbine and a hydropump. In this case, the casing 1 in the case of such a fluid flow machine or turbomachine can form a single casing or an inner casing of a double casing or an outer casing of a double casing. The casing 1 can also form a stator blade carrier or a seal carrier of such a fluid flow machine or turbomachine. The casing 1 is preferably designed in an rotationally symmetrical manner at least in a region which is provided with the coil 6. The outer sides of the two abutting half-casings 2, 3 preferably have an outer contour 10 which corresponds to a shell of an rotationally symmetrical body and is therefore circular in cross section. In the example according to FIG. 1, the casing 1 has a constant cross section and is cylindrically designed accordingly. Casings 1 which have a cross section which varies in the axial direction are also conceivable. Conical or frustoconical-shaped casings 1 or casing sections are especially conceivable. Casings 1 with their outside diameter altering in steps are shown in FIG. 4 and FIG. 5. The cylindricity of the external surfaces of the casing sections which are identified by 42 for example has the advantage that the tension cable 7 cannot slip sideways and that the pretensioning is not consequently lost. The casing sections 42 are axially delimited by means of casing collars 43.

In the case of a casing 1 with such a coil 6, this can also be combined with conventional casing connections. For example, the casing 1 according to FIG. 6 can be equipped with a conventional bolted flange connection 33 in one longitudinal section, and in another longitudinal section, which is preferably associated with the hotter side of the casing 1, can be provided with a wire coil connection 34 of the previously described type. In the same way, according to FIG. 7 the casing 1 can be equipped with a conventional shrink ring connection 35 in one longitudinal section, and in another longitudinal section, which is preferably associated with the hotter side of the casing 1, can be equipped with a wire coil connection 34 of the aforementioned type. The bolted flange connection 33 from FIG. 6 comprises flanges 47 with flange holes 44 for connecting bolts. The shrink ring connection 35 from FIG. 7 comprises bearing surfaces 45 for shrink rings 46.

Each tension cable 7 inevitably has two ends which are not identified here in more detail. These ends of the respective tension cable 7 can be fastened on the casing 1 via corresponding anchor points, which are not shown here. These anchor points for example can be attached on a casing collar 11 or on the cylindrical wire bearing surface. One cable end, however, can also be connected to another cable end of the same cable or of another cable. For example, two wire ends can be welded to each other. Also, an eye can be attached on each cable end, wherein the eyes are then connected by means of a preferably retensionable clamp.

With the coil 6 completed, the respective tension cable 7 is loaded under tension. The tension can be introduced into the casing 1 or into the half-casings 2, 3 via the anchor points 11. The pretensioning of the coil 6 or of the respective tension cable 7 can therefore be dissipated inside the casing 1. According to an especially advantageous embodiment at least one of the anchor points 11 can be designed so that retensioning of the respective tension cable 7 can be carried out with it.

The coil 6 can basically be configured with a single layer. This means that the individual windings of the respective tension cable 7 are arranged next to each other exclusively in the axial direction. A multilayer configuration of the coil 6 is also possible. FIG. 1 exemplarily shows a double-layer configuration of the coil 6, as a result of which individual windings are adjacently arranged in the radial direction as well. Coils 6 with more than two coil layers are also conceivable. To configure the coil 6 so that each coil layer is produced from only a single tension cable 7 is especially conceivable, wherein each winding layer preferably comprises a separate tension cable 7 of its own in each case. By the same token, in the case of a single-layer or multilayer construction of the coil 6 it is possible to construct the respective coil layer from a plurality of tension cables 7. It is clear that for each specific number of tension cables 7 the fastening device 5 has a number of anchor points 11 which are complementary to them.

If the coil 6 is constructed from a plurality of different tension cables 7, provision can basically be made to configure individual tension cables 7 differently with regard to cable thickness or cable diameter and/or with regard to the wire material which is used. As a result of this, it is especially possible to reduce the cable thickness 9 in higher-loaded regions in order to increase the winding density or to increase the cable thickness in just these regions in the case of a single-layer construction. Wire materials of different strengths corresponding to the strength requirements can also be used. For example, an embodiment is conceivable in which a plurality of winding layers are provided, wherein different tension cables 7 are used in different winding layers. Also, different axial regions, which are enwrapped by different tension cables 7, can be formed along the casing 1. In the case of a casing 1 with variable temperature in the axial direction, as customarily happens for example in an inner casing of a steam turbine, the wire material in the colder regions can be produced from less expensive material and in the hotter regions produced from material which is more resistant to heat. In the case of a casing 1 with temperature which decreases in the radial direction, as customarily happens for example in an outer casing of a steam turbine, the wire material in the hotter first inner winding layers can be produced from material which is more resistant to heat and in the colder outer winding layers produced from less expensive material.

According to FIG. 2, it can be expedient to position the two half-casings 2, 3 relative to each other by means of centering pins 12. These centering pins 12 in this case are arranged in the region of the contact plane 4 and are inserted in corresponding centering holes 13 which are preferably formed in each case in a boundary region of the respective half-casings 2, 3. The centering holes 13 or the centering pins 12 in this case are oriented perpendicularly to the parting plane 4. When assembling the half-casings 2, 3 the centering pins 12 enable the locating of a desired relative position between the two half-casings 2, 3. Especially advantageous in this case is the embodiment which is shown here in which the centering pins 12 are attached on the half-casings 2, 3 so that they are located entirely inside the outer contour 10 of the casing 1 in each case, as a result of which a completely recessed arrangement for the centering pins 12 is created. As a result of this, interference of the coil 6 by means of the centering pins 12 does not occur.

According to FIG. 3, in the case of another advantageous development provision can be made to fasten the half-casings 2, 3 to each other by means of securing screws 14. These securing screws 14 in this case serve essentially only for securing the relative position between the half-casings 2, 3 which is located by means of the centering pins 12. The securing screws 14 in particular are not able to apply the retaining forces between the two half-casings 2, 3 which are necessary for the operation of the fluid flow machine which is equipped with the casing 1. They therefore serve only for facilitating installation. For installation of the securing screws 14, for example each half-casing 2, 3 is provided with through-holes or through-bores 15, as a result of which it is possible to insert the respective securing screw 14 and to form a threaded connection with a complementary securing nut 16. Also in this case, one embodiment is preferred in which the securing screws 14, including the associated securing nuts 16, are attached on the half-casings 2, 3 so that they are arranged entirely inside the outer contour 10. As a result of this, a completely recessed arrangement of the securing screws 14 or of the securing nuts 16 can be achieved, which simplifies the attaching of the coil 6.

FIGS. 8 to 12 show installation devices 17 by means of which such a coil 6 can be attached on such a casing 1. The respective installation device 17 in this case comprises an abutment device 18 which is attached in a fixed manner on the respective casing 1, or can be at least temporarily attached in a fixed manner on the casing 1, for installation or for removal. In addition, each installation device 17 comprises at least one tensioning device 19 which is designed so that it is either permanently supported on the abutment device 18 or can be at least temporarily supported on the abutment device 18. In addition, the respective tensioning device 19 is designed so that a tensioning force can be introduced into the respective tension cable 7 with it.

In the case of the embodiment which is shown in FIGS. 8 and 9, the abutment device 18 comprises a plurality of insertion holes 20 which for example are incorporated radially into the half-casings or into a corresponding collar on the outside and which are arranged adjacent to each other in the circumferential direction. The respective tensioning device 19 in this case comprises a tensioning lever 21 which can be inserted by a foot 22 into the insertion holes 20 and can therefore be anchored on the abutment device 18 or on the casing 1. The tensioning lever 21 is pivotably mounted by its foot 22 on a pivot 23. A clamp fitting 25 is pivotably mounted on the tensioning lever 21 at 24. The clamp fitting 25 is designed so that it can be connected to the tension cable 7 for introducing tensioning force. The clamping action can be created for example by screws, which are not shown here, clamping the clamping jaws of the clamp fitting 25. The clamping effect, however, can also be carried out by the clamping jaws being designed in the shape of a wedge and automatically being clamped as a result of the friction between the clamping jaws and the cable and the applied cable tensioning force. This principle is frequently applied for example when clamping test pieces in universal tension testing machines.

The non-essential, but helpful, tension spring 26 enables a large displacement movement of the clamping lever 21 to be possible and the cable tension to be able to be accurately adjusted since as a result of the displacement movement of the tensioning lever 21 the tension spring 26 is stretched and a cable tensioning force is created which is adjustable by selection of the spring compliance.

The tensioning lever 21 in this case serves for actuating the clamp fitting 25. By manual operation of the clamping lever 21, for example according to an arrow 27, comparatively large tensioning forces can be introduced into the tension cable 7. This installation device 17 operates for example with two such tensioning devices 19 which, displaced in the circumferential direction, are applied one after the other so that for example with the first tensioning device 19 a tensioning force can be introduced and maintained in the tension cable 7, while at the same time the second tensioning device 19 can be applied at another position on the tension cable 7 in order to undertake the introduction of the tensioning force so that the first tensioning device 19 can subsequently be removed again for repositioning. The tensioning devices 19 can therefore be displaced in the circumferential direction along the abutment device 18 corresponding to the spacing of the insertion holes 20. According to FIG. 9, the tensioning lever 21 can be configured in the shape of a Y and via two feet 22 can be supported in each case at two positions on the abutment device 18.

In the case of the embodiment which is shown in FIG. 10, the abutment device 18 comprises a rail 27 which is anchored in a fixed manner to the casing 1 via supports 32. A slide 28, which forms a component part of the tensioning device 19, interacts with the rail 27. The slide 28 in this case is adjustable along the rail 27, that is to say in the circumferential direction with regard to the casing 1. For this purpose, the tensioning device 19 can be equipped with a drive, which is not shown, which enables the tensioning device 19 or the tensioning lever 21 to be adjusted along the abutment device 18 or along the rail 27, that is to say in the circumferential direction of the casing 1. Furthermore, the tensioning device 19 in the case of the embodiment which is shown here can have a further drive 30 which ensures unwinding of the tension cable 7, while maintaining the desired tension, during the adjusting movement of the tensioning device 19 in the circumferential direction of the casing 1.

Furthermore, such an embodiment can include a slide 29 which can be displaced in the axial direction of the casing by a drive, which is not shown here, and as a result can achieve the pitch 8 (see FIG. 1) of a helical cable coil. The drives for the circumferential movement of the slide 28 and for the axial movement of the slide 29 are preferably matched to each other in order to maintain the desired helical shape of the cable coil 6.

In the case of a further tensioning device according to FIG. 11, the tension cable 7 is initially wound on a reel 36 which is provided with a rotational drive, wherein the rotational drive is fastened on a slide 37 which is movable in the axial direction of the casing and provided with a drive, wherein a rail 38 of this slide 37 is connected to the floor 39 in a fixed manner. The casing 1 in turn is rotatably mounted around the axis of the casing, wherein the rotational movement is also implemented by a drive. Corresponding casing bearings 40 are also connected to the floor 39 in a fixed manner. The cable coil is created by the casing 1 being rotated after fastening the tension cable 7 on the casing 1, while the rotational drive of the reel 36 unwinds the cable 7 from this reel 36, in fact so that the cable tensioning force corresponds to the predetermined value, i.e. the rotational drive of the reel 36 is load-controlled and not distance-controlled. At the same time, the axial slide 37 is moved by means of its drive so that the desired pitch 8 of the winding helical shape is achieved. Furthermore, 48 identifies the direction of rotation of the casing 1, 49 the winding-up direction of the cable 7, 50 the direction of rotation of the reel 36, 51 the direction of force of the reel 36, and 52 the bearing of the reel 36.

FIG. 12 includes the same tensioning device as FIG. 11, but with the difference that a spring 41 is additionally installed on the axial slide 37. With this spring 41, it is simpler to adjust the tension of the tension cable 7 since a small rotational movement of the reel 37 then brings about only a small change of the tensioning force in the tension cable 7. Without this spring 41, the change of the tension force would be much greater and controlling the drive of the reel 37 would be therefore more difficult.

LIST OF DESIGNATIONS

-   1 Casing -   2 Half-casing -   3 Half-casing -   4 Parting plane -   5 Fastening device -   6 Coil -   7 Tension cable -   8 Pitch -   9 Cable diameter -   10 Outer contour -   11 Casing collar -   12 Centering pin -   13 Centering hole -   14 Securing screw -   15 Through-hole -   16 Securing nut -   17 Installation device -   18 Abutment device -   19 Tensioning device -   20 Insertion hole -   21 Tensioning lever -   22 Foot -   23 Bearing -   24 Bearing -   25 Clamp fitting -   26 Spring -   27 Rail -   28 Slide for circumferential movement -   29 Slide for axial movement -   30 Drive -   31 Force introduction -   32 Support -   33 Bolted flange connection -   34 Wire coil connection -   35 Shrink ring connection -   36 Reel -   37 Slide -   38 Rail -   39 Floor -   40 Casing bearing -   41 Spring -   42 Casing section -   43 Casing collar -   44 Flange hole -   45 Bearing surface -   46 Shrink ring -   47 Flange -   48 Direction of rotation -   49 Winding-up direction -   50 Direction of rotation -   51 Direction of force -   52 Reel bearing 

1. A casing of a fluid flow machine comprising: two half-casings (2, 3) which abut against each other on an axial parting plane (4), a fastening device (5) for the fastening to each other and for the pretensioning of the two half-casings (2, 3) against each other, wherein the fastening device (5) includes at least one coil (6), comprised of at least one tension cable (7) which is loaded under tension and comprises at least one wire, which wraps around the half-casings (2, 3) on the outside.
 2. The casing as claimed in claim 1, wherein ends of the respective tension cable (7) are fastened on the casing (1) via anchor points (11).
 3. The casing as claimed in claim 2, wherein at least one of the anchor points (11) is adapted to retension the respective tension cable (7).
 4. The casing as claimed in, claim 1, wherein the casing (1) is rotationally symmetrical at least in the region of the respective coil (6).
 5. The casing as claimed in claim 1, wherein the half-casings (2, 3) in the region of the parting plane (4) are positioned relative to each other via centering pins (12) which are particularly arranged in a recessed manner entirely inside an outer contour (10) of the casing (1) which supports the coil (6).
 6. The casing as claimed in claim 1, wherein the half-casings (2, 3) are fastened to each other by securing screws (14) which are particularly arranged in a recessed manner entirely inside an outer contour (10) of the casing (1) which supports the coil (6).
 7. The casing as claimed in claim 1, wherein the coil (6) comprises at least one layer, and/or for each coil layer the coil (6) comprises at least one tension cable (7), and/or the coil (6) comprises a plurality of different tension cables (7) which wrap around the half-casings (2, 3) in different coil layers and/or in different axial regions of the casing (1), and differ from each other with regard to cable thickness (9) and/or wire material.
 8. The casing as claimed in claim 1, wherein the casing (1) is an inner casing or an outer casing or a single casing or a stator blade carrier or a seal carrier of a steam turbine or of a gas turbine or of a hydroturbine or of a hydropump or of a compressor.
 9. An installation device for attaching a coil (6) on a casing (1) as claimed in claim 1 comprising: an abutment device (18) which is attached, or can be attached, in a fixed manner on the casing (1), at least one tensioning device (19) which is supported, or can be supported, on the abutment device (18) for introducing a tensioning force into the tension cable (7).
 10. The installation device as claimed in claim 9, wherein the abutment device (18) encompasses the casing (1) in the circumferential direction, and/or the at least one tensioning device (19) can be adjusted or displaced along the abutment device (18) in the circumferential direction, and/or the at least one tensioning device (19) has a tensioning lever (21) for actuating a clamp fitting (25) which can be connected to the tension cable (7) for tensioning force introduction, and/or the at least one tensioning device (19) has a drive (29) for adjusting the tensioning device (19) along the abutment device (18). 